Last Thursday, I made the trek up to the Metropolitan Pavilion in New York City to check out the annual CE Week show. And I must say that it wasn’t nearly as valuable an experience as it was a few years ago, when the show was affiliated with the Consumer Technology Association.
If my understanding is correct, CE Week was a way to keep interest stoked in the rapidly-changing world of consumer electronics. When the show first started, HDTV was a big part of the equation, with exhibitors like Samsung, Sony, Toshiba, Mitsubishi, Sharp, and LG either showing off their latest models on the show floor, or exhibiting at nearby off-site locations.
That landscape has changed considerably, thanks to the collapse in TV prices and the shift to panel manufacturing in China. Only two companies had dedicated exhibits for UHD TVs – Samsung and Westinghouse Digital – while other models were represented in the annual Value Electronics Shoot-Out in a downstairs demo room.
Once arriving at the event, I quickly toured the booths and saw products to connect your landline phone calls to your mobile (Voice Bridge), give you a 360-degree camera view (Kodak PixPro), “enhance” the detail in your new Ultra HDTV (DarbeeVision), and bundle audio and large images into a compact go-anywhere cube projector (Aiptek). (I was also buzzed by a few drones here and there, the fastest being a $60 glowing green/blue number sold by Odyssey that really whipped around the show floor.)
Epson was also there, showing a full line of front projectors for home theater use, including a new model (PowerLite 5040UB) that, although it uses a traditional 1920×1080 3LCD engine, incorporates a new “4K Enhancement Technology” that uses pixel-shifting to create what appears to be images with full 3840×2160 resolution. (Oh, and it can display HDR content, too. Oh, and it will cost about $3,000, and its full brightness specification is 2500 lumens.)
Scoping out all of that stuff took only about an hour, so I decided to descend the stairs and check out the UHDTV Shoot-Out, put together by Robert Zohn of Value Electronics. There had been some arguments among videophiles in the past about the winners (Shoot-Outs tend to end that way, trust me), so I decided to keep a low profile and sit in the very back as a passive observer, passing on the evaluations and scoring.
Joel Silver was on hand from the Imaging Science Foundation to explain a wide range of TV topics from grayscales and CIE color plots to high dynamic range and black levels. After discussing each parameter, those in attendance were invited to walk by each of the five displays and score them on performance for that parameter. At the end of the session, the votes would be tabulated and a winner announced.
For the record, the UHDTVs on hand came from LG (OLED), Samsung (HDR LCD), Sony (HDR LCD), and Vizio (HDR LCD). Just for fun, an older Pioneer 1080p plasma TV was also positioned to the left edge of the array, next to the LG OLED.
The introduction of high dynamic range with wider color gamuts (and eventually, higher frame rates) really does change the notion of television from what we know today. Instead of a nominal peak white brightness of 100 to 200 cd/m2, we’re now looking at 800 to 1000 cd/m2. And the range of colors our displays can reproduce has expanded considerably, particularly in the green and red loci. So viewing HDR/WCG content really is a step closer to what our eyes see every day, and makes conventional SDR HDTV look a bit dated.
As the session wound on, I noticed that the grayscale images shown on the LG OLED (model OLED65G6P) had a noticeable greenish color cast that wasn’t seen on the other sets. Intrigued, I got up and walked over to stand at a zero degree offset from the TV’s centerline – and voila: The tint vanished.
Additional images with lots of white, light grays, and pastel colors were shown during the test, and I moved back and forth between the on-axis viewing spot (several rows of chairs back from the audience) and my original seat at the far left rear, which looked to be about 30 – 35 degrees off-axis. Sure enough, the greenish color tint was still there.
I pointed this out to a couple of LG representatives, neither of whom had noticed it previously. I also mentioned it to Zohn, who replied that he also noticed it before but stated “it’s still the best thing out there.” Uh, maybe not, if someone viewing at a moderate angle is seeing a greenish tint that someone else isn’t. None of my plasma TVs ever exhibited this condition.
Silver told me he doesn’t recommend using these displays for color grading or critical viewing because of an inconsistency in yellow shading. I didn’t notice that, but it was hard to miss the green shift. I alerted a few other people in the room to look for it, including my colleague Ken Werner. (You can see it quite clearly in my photos.) But if you were one of the crowd seated in the first couple of rows toward the center, you wouldn’t have seen this “fly in the ointment.”
Even so; this display won the Shoot-Out, according to a press released that landed in my inbox this morning. Quote: “LG Electronics’ SIGNATURE 4K OLED TV was crowned “2016 King of TV” in the 13th Annual Value Electronics TV Shootout™ in a competition among four contending flagship 4K Ultra HD TV models from LG and other leading brands during CE Week in New York City. The 65-inch class (64.5 inches measured diagonally) LG SIGNATURE OLED TV (model OLED65G6P) with HDR was voted the top-performing TV by both general attendees and an expert panel of professional calibrators based on eight different picture quality attributes.”
Hmmm. I’m surprised that the “expert panel of professional calibrators” didn’t pick up on the LG color shift, particularly since models of LCD TVs are routinely hammered for their intrinsic off-axis viewing limitations (elevated black levels, color shifts, and contrast flattening). So what’s causing it?
I have some theories. Several years ago, Sony introduced its first OLED monitors for professional reference monitoring. To improve color purity and make it easier to achieve clean white balance (and possible to improve brightness as well), Sony’s top-emitting OLED pixels were equipped with cavity filters – basically narrowband (notch) optical filters.
Unfortunately, these cavity filters created an unwanted low-frequency roll-off effect when images were viewed at an angle, producing a marked blue color shift on the parts of the image farthest from a viewer. This effect was most noticeable when grayscale patterns were being shown. (My understanding was that Sony re-engineered the design of these filters to improve off-center frequency response in subsequent models.)
So is that what caused the color shift in LG’s 65-inch Signature OLED UHDTV? Possibly. Using these filters could flatten out and sharpen the red, green, and blue peaks, although a color gamut chart shown by Silver seemed to contradict that theory.
It’s also possible LG is using some sort of micro lens or prism technique (or even a polarizer) in the optical path to enhance brightness, and that could be the problem. The result would be brighter images with excellent color saturation, but a narrower viewing angle. (Everything in life is a trade-off!)
Does this affect all models of LG OLEDs? I can’t say, and I don’t recall seeing anything like this at CES when visiting the LG booth and LG Display suite and taking pictures of various OLED displays at different angles. I’ve sent off an inquiry to LG Display to see if they can provide any insights. And my congratulations go to LG for winning the Shoot-Out. (Hey, that 10-year-old Pioneer plasma still looks pretty good!)
But as much as I prefer emissive (plasma, OLED) displays over transmissive (LCD), what I saw at the CE Week TV Shoot-Out gave me real pause. In my family room, viewing angles can be as wide as 40 degrees, and as you’ve just seen, the color shift would be very noticeable at that angle.
Prior to attending CE Week, I had planned to pick up an OLED UHDTV next year, after all the HDR compatibility and support issues (and hopefully display interface speed limit problems) are worked out. Now? That’s on hold until I can figure out what’s behind the shift, and if it’s a characteristic of other 2016 LG OLED TVs.
Those flies in the ointment can be quite annoying!
Posted by Pete Putman, June 27, 2016 10:05 AM
About Pete PutmanPeter Putman is the president of ROAM Consulting L.L.C. His company provides training, marketing communications, and product testing/development services to manufacturers, dealers, and end-users of displays, display interfaces, and related products.
Pete edits and publishes HDTVexpert.com, a Web blog focused on digital TV, HDTV, and display technologies. He is also a columnist for Pro AV magazine, the leading trade publication for commercial AV systems integrators.